An electronic system may include interconnected circuit boards, such as daughter boards, motherboards, backplane boards, midplane boards, or the like. The circuit boards may be interconnected with one or more connector assemblies. A typical connector assembly for a midplane board may include two header connectors, each attached to opposite sides of the midplane board. The two daughter boards that interconnect with the midplane board each may have a complementary connector that mates with the respective header connector. Typically, the connectors are part of a connector family, manufactured according to an established format.
The header connectors each may have a respective mounting contact. The circuit board may have one or more holes or “vias” that receive the mounting contacts. In some applications, the mounting contacts extend into the same via from either side of the circuit board. The via may be plated to provide electrical conductivity between the respective mounting contacts, and thus, between the respective daughter boards.
Multilayer circuit boards may have a number of conductive signal layers insulated from each other by dielectric layers. The conductive signal layers may provide high density communication between components because more than one layer is available for communication between components. Because the signal layers are parallel to each other, in multilayer boards, plated vias provide a conductive path between and/or among signal layers. These paths allow for complex circuit design and flexible routing of signals from one layer to another layer.
Electronic applications may benefit from a shared via architecture and multilayer midplane boards. For example, it may be desirable to have some signal paths, such as low-speed communication paths, route from a daughter board to a signal layer of the midplane board. However, such designs may be problematic, particularly with standard connectors in an orthogonal orientation. Because the vias are typically plated from end-to-end, a shared via providing connectivity to the midplane may inherently provide an undesirable, concurrent connectivity between mounting contacts.